Sensors are often used to measure a motion of an object. For example, vibratory meters typically use sensors to measure the position, velocity, or acceleration of a tube. In particular, the vibratory meter can use a driver to vibrate the tube filled with material such as a fluid. The sensors can measure a movement of the tube to determine properties of the fluid in the tube. For example, a sensor can be coupled to the tube filled with material proximate a first fluid port and a second sensor can be coupled to the tube filled with material proximate a second fluid port. The time delay between the first and second sensor can be proportional to the flow rate of the material. The time delay can be determined from two signals provided by the first and second sensors. The two signals are typically analog signals.
Electronics in the vibratory meter can condition the analog signals with operations such as filtering, amplification, or the like, so the analog signals can be digitized. The electronics that condition the analog signals may be sensitive to the temperature changes. For example, the cutoff frequency of a low-pass filter can increase due to increases in temperature of an operational amplifier in the low-pass filter. Other electronic components, such as, for example, diodes, capacitors, inductors, and resistors can also cause output variations that are due to temperature changes in and around the electronics.
The vibratory meter is typically installed in environments with a wide range of temperature specifications. For example, the vibratory meter may be installed on an oil platform where the ambient temperature can be about −40° C. and then later moved to a different oil platform where the temperature can be over 50° C. In addition, the temperatures around the electronics can vary due to electrical current heating the electronic components. Other sources of uncontrollable temperature changes may also be present, such as extremely low fluid temperatures in cryogenic applications. As a result, the signals from the sensors can change due to temperature variation while being conditioned by the electronics.
Accordingly, there is a need for temperature compensation of a signal in a vibratory meter. There is also a need for temperature compensation of the signal affected by temperature variations in and around the meter electronics of the vibratory meter.